Pneumatic cushion for elevators



C. A. ELLIS 8v E. S. MILLER. PNBUMATIG CUSHION FOR BLEVATORS.

(No Model.)

No. 572,531. Patented 1360.8, 1896.

L' 2 an@ l', en

UNITED STATES PATENT OFFICE.

CHARLES A. ELLIS AND EDMUND S. MILLER, CF KANSAS CITY, KANSAS.

PNEUMATIC CUSHION FOR ELEVATRS.

SPECIFICATIN forming part of Letters Patent No. 572,531, dated December8, 1896.

Application filed February 17, 1896. Serial No. 579,627. (No model.)

To @ZZ whoml t may concern;

Be it known that we, CHARLES A. ELLIS and EDMUND S. MILLER, of KansasCity, Wyandotte county, Kansas, have invented certain new and usefulImprovements in Pneumatic Cushions for Elevators,'of which the followingis a full, clear, and exact description, reference being had to theaccompanying drawings, forming a part thereof.

Our invention relates to pneumatic cushion s for elevators, and moreparticularly to a cushion which will bring the elevator-cage to agradual stoppage no'matter what the speed or velocity of descent may be.

A further object is to produce a pneumatic cushion which will notinterfere in the slightest degree with the regular operation of theelevator and to produce apparatus embodying theseadvantages which aresimple, stronO. durable, and inexpensive of construction and which maybe mounted or arranged in proper position with little difficulty orlabor.

To these ends the invention consists in certain novel and peculiarfeatures of construction and combinations of parts, as will be'hereinafter described and claimed.

In order that the invention may be fully understood,we will proceed todescribe it with reference to the accompanying drawings, in which-Figure l represents an elevator-shaft provided with an elevator-cage andpneumatic cushion embodying our invent-ion. Fig. 2 represents ahorizontal section taken below the elevator-cage and on an enlargedscale.

Fig. 3 represents in detail and in section the plunger carried by theelevator-cage. Fig. 4 represents a vertical section of the escapevalve,which is adapted to yield under great pressure and permit the escape ofair. Fig. 5 is a detail sectional view enlarged.

In the said drawings, l designates an elevator-shaft; 2,an elevator caror cage therein; 3, a cable or cables by which it is suspended orsupported,and 4 designates a vertical pneumatic tube which is mountedvertically and centrally of the shaft and extends downward from thelevel of the irstfloor, approximately, to a suitable depth. Its lowerend is closed by the disk or flan ge 5, and it is held rmly and rigidlyin position upon the foundation structure G by means of the bolts 7,which extend through said foundation structure.

8 designates a horizontal pipe which communicates with the tube 4 aboveits middle, and 9 a vertical pipe which communicates with the outer endof the pipe S by means of an elbow or other suitable coupling.

lO designates a hollow cap which screws upon the upper end of the pipe9, which upper end projects above the ground-floor at any convenientpoint where it is out of the way. Said cap is provided with two seriesof holes or apertures ll and l2, one series being above the other, andthe lower series l1 being just above the upper end of the pipe 9. Theupper end of the cap is centrally perforated, as shown at 13, andengaging the same and guided therein is the stem of a disk valve 14,which normally occupies a plane coincident with the lowerseries of holesand thereby prevents the escape of air from the pipe 9 at its upper end.Said valve in such position rests squarely and iirm ly upon the upperend of said pipe and is held yieldingly thereat by means of thecoil-spring 15, arranged spirally around its stern and bearing at itsopposite ends against the valve and the upper end of the cap.

16 designates a rod or stem about the same length as the tube 4, whichis arranged to depend vertically and centrally with relation to theelevator car or cage, it being providedat its upper end with a flange orbase-plate 17,

which is secured rigidly and firmly to the bottom of the elevator car orcage by means of bolts 18 or equivalent devices, and formed at orsecured to the lower end of said rod is a head or piston 19, which isadapted to fit snugly Within the tube 4 when the car or cage is at thelower end of the shaft, and for convenience and to insure the pistonproperly entering said tube the latter is preferably flared outwardly atits upper end or mouth. This piston is provided with a series ofvertical air-passages 20.

2l designates a pipe communicating at its opposite ends with the lowerend of the tube 4 and the pipe 22, which latter at its upper end isprovided with a globe valve 23, and below the same with a T-coupling 24,which,

carries abranch pipe 25, provided with a IOO check-valve 2G, adapted toclose tightly with the air-pressure caused by the descent of the plungerwithin the tube and to open with the opposite or upward movement of thepiston, so that air is drawn into the lower end of the tube ma the pipes25, 22, and 21. It also enters the same by way of the passages 2O of theplunger I9 when provided with such.

In practical operation as the car travels up and down within the shaftunder the control of the actuating machinery it is practicallyunaffected by the pneumatic-cushion apparatus, owing to the fact thatits descent is comparatively slow, and consequently when the pistonenters and moves downward to the bottom of the tube 4 the air iscompressed within said tube so slowly that it has ample time to escapeupwardly through the passages 20 of the piston without affecting theposition of the spring-actuating valve 14C in the slightest degree, andas it moves upward air enters the tube below the piston, and by givingit free vent in this manner prevents any suctional resistance to theupward movement of the plunger, which would unavoidably follow if therewas no means of admitting air to the bottom of the tube when the plungerstarted to rise. Vhen it descends with great velocity or speed, however,because of the breakage of the supporting mechanism or other cause, thepiston moves downward in the tube with suoli rapidity that only acomparatively small volume of air can escape upwardly through theopenings 20, and the great air-pressure thus generated forces the valvel-i upward from its seat against the resistance of the spring l5, and alarge volume of air escapes by way of the holes or perforations 1l, orll and 12. Thus it will be readily understood that as the air is heldtightly compressed by the downwardlymoving piston the car or cageisbrought to a gradual stop positive and reliably and is not arrested assuddenly as it would be if no provision were made for the escape of air,it being also clear that if the passages 2O alone were provided for thispurpose the air could not escape with sufiicient rapidity to preventmore or less concussion as the car suddenly stopped. After the speed ofthe downwardly-moving plunger is thus yieldingly checked it movesdownward to the bottom of the tube by the further compression of the airwithin the tube and also by reason of the passages 20, through which asmall volume of air escapes and permits the elevator car or cage todescend to the lowest landing.

It is to be understood, of course, that the substitution of mechanicalequivalents for parts of this apparatus, such, for instance, as the useof a weighted valve (like the safetyvalves on steam-boilers) instead ofour springactuated valve, may be made without departing from the spiritand scope of our invention; but the struct-ure shown is preferred,because it is simpler, more compact, and less expensive of manufacture.

I-Iaving thus described the invention, what we claim as new, and desireto secure by Letters Patent,- is Y l. In combination with an elevatorcar or cage, a piston depending vertically and centrally therefrom, apneumatic tube arranged to receive the same below the lower landing orfloor, a pipe communicating with the tube above its middle, a perforatedcap for the upper end of said pipe, and a spring-actuated valve withinsaid cap, and seated normally upon the upper end of said pipe,substantially as shown and described.

2. In combination with an elevator car or cage. a vertically-perforatedpiston depending vertically and centrally from and carried by said caror cage, a pneumatic tube having its lower end closed and its upper endopen, and arranged' with its upper end about coincident with the bottomiioor or landing of the building wherein the elevator is located, andbolted to a suitable foundation at its lower end, a -pipe communicatingwith said tube above its middle, a perforated cap upon its upper end, aspring-actuated valve within said cap and normally seated to prevent theescape of air from said pipe, a second pipe communicating with t-helower end of said tube and with the outside air, and provided with aglobe-valve and a check-valve, all arranged substantially as and for thepurpose set forth.

. In testimony whereof we affix our signatures in presence of twowitnesses.

CHARLES A. ELLIS. EDMUNDS. MILLER. \Viti1esses:

J. L. CARLIsLE, F. M. MILLER.

